Turntable Motor

[booangler]

Hello All,

Can someone tell me the purpose of the capacitor in this diagram? https://docs.google.com/file/d/0B5DyIacd8HbieUFXQnlZeWJ1MEE/edit?usp=sharing

Also, how much filtering of the 24v AC power supply am I going to need to maintain a steady speed suitable for use in a TT?

[Paul Birkeland]

Hello All,

Can someone tell me the purpose of the capacitor in this diagram? https://docs.google.com/file/d/0B5DyIacd8HbieUFXQnlZeWJ1MEE/edit?usp=sharing

Also, how much filtering of the 24v AC power supply am I going to need to maintain a steady speed suitable for use in a TT?

That is a motor run capacitor.

I don't understand the AC filtering question, what are you attempting to accomplish?

[booangler]

Mr Blackplate,

A friend is try to build himself a TT but he has little experience with circuitry so he asked me to look at the diagrams. The packaging came with way more diagrams than I included. I was able to get him started in the right direction at least. He then asked me about the purpose of the capacitor to which I didn't have an answer but do know. He also asked me how complex power he would need. Seems that in his research he has seen articles and post that indicate some builders go a to great lengths designing the supplies. I hindsight my choice of words may have been incorrect. To restate the question:

Would a simple 120 to 24 volt transformer work for a turntable supply or do I need to tell him to look for something better designed than that?

Also, does the type and quality of the cap used for the motor start have any impact on the motor performance?

Thanks,

Alan

[Paul Birkeland]

I wouldn't go nuts on the quality of the cap.  Likely, there will be different values specified for this capacitor depending on whether or not your AC is 50 or 60Hz.

Something like thiswill be sufficient to get you started unles the motor requires more power.

If the wall power available has a frequency that fluctuates, then you can go through all the effort to build a regenerator.

[booangler]

Thank you Paul.

One more question for you?

Will this work for the cap? 5.6 was the specified size for the Cap. I stepped up the voltage simply to create a safety margin.

Cheers,

Alan

[Paul Birkeland]

It's funny, I've never seen a Tantalum capacitor used as a motor run cap.  A quick search yields no solid answer for this, but I suspect that they may have some performance limitations just based on how small they are. 

Usually you see something like this.

[booangler]

PB,

We are going to do some experiments once more of the parts get in. I will report back our results.

My Best,

Alan